[antlr-interest] .g vs .g4

[Michael Bedward]

I feel your pain Kirby and while I remain unconvinced about the evil
of file extensions in a general sense (I'd hate to have to rewrite all
my file gathering scripts to grep contents) I guess ANTLR 4 grammar
files could be identified by a header element. However, I'd still vote
for a g4 suffix on the grounds that it is simple and obvious to users
and applications.

That said, in my previous life as a C++ grafter I would have felt very
uncomfortable using anything other than .h or .hpp for header files :)

Michael